you may use method similar to the one used for bookmarks in manipulate
here is simple example
ClearAll[a, b, c];
vals := {a = 4, b = 3, c = 4};
Save[NotebookDirectory[] <> "\\1.val", vals]
vals := {a = 5, b = 3, c = 4};
Save[NotebookDirectory[] <> "\\2.val", vals]
ReSet[] :=
DynamicModule[{},
Dynamic[TableForm[Table[InputLine[pp[][[i]]], {i, Length[iv]}]]]]
InputLine[{p_, q_}] :=
DynamicModule[{t},
ReleaseHold[Row[{p, InputField[Dynamic[t]]}] /. t :> q]]
ButtonReSet[] := Button["reset values", vals]
ButtonBrowse[] :=
Button["browse for New values",
With[{xfile = SystemDialogInput["FileOpen",
{NotebookDirectory[], {"val file" -> {"*.val"}}},
WindowTitle -> "load your settings..."]},
If[xfile =!= $Canceled, Get[xfile]; vals]], Method -> "Queued"]
F[] := DynamicModule[{}, Dynamic[Plot[a x^2 + b x + c, {x, -1, 1}]]]
ClearAll[pp, a, b, c];
iv = {a, b, c};
pp[] := {{"coff a ", Hold[a]}, {"coff b ", Hold[b]}, {"coff c ",
Hold[c]}};
vals := {a = 2, b = 3, c = 4};
Dynamic[#] & /@ iv
ReSet[]
F[]
Row@{ButtonReSet[], ButtonBrowse[]}